Use the real app
College Board puts full length practice tests inside Bluebook, the same app you will use on test day. They are free, they are adaptive the way the real test is, and they run the same tools: the annotator, the answer eliminator, the flag, and the built in Desmos calculator on Math.
That last part is the argument for using them over a PDF. A printed practice test cannot route you into an easier or harder Module 2, and it cannot teach you where the Desmos panel sits on screen. Both of those are things you want to have already dealt with before the real morning.
Third party tests are useful for drilling one skill at a time. For a full length timed run, use the official ones.
The graph of the linear function f is shown in the xy-plane. What is the y-intercept of the graph of y = f(x)?
How to sit it
One sitting, timed, phone in another room. Reading and Writing first as two 32 minute modules, then the 10 minute break, then Math as two 35 minute modules. Do not pause a module, do not look anything up, and do not take the break for an hour.
Do it in the morning if you can, because that is when the real test happens and your concentration at 8am is not the same as your concentration at 9pm. Sit at a desk, not in bed.
Sustaining attention for 2 hours and 14 minutes is itself a skill. If you have never done it, the last Math module of your first practice test is going to feel much worse than the first Reading and Writing module, and that gap is the thing practice tests fix.
Roughly every other week during a serious study block, and no more than one a week ever.
How often to take one
Roughly every other week during a serious study block, and no more than one a week ever. A full test plus a real review is four or five hours of work, and taking them back to back leaves no time to fix anything between them.
If you have twelve weeks, that is about five or six full tests. If you have four weeks, two or three is right. In the final two days, take none. There is nothing left to learn from one and you will arrive tired.
The review is the point
Go through every question you got wrong and sort it into one of three buckets: you did not know the content, you knew it but made an error, or you ran out of time. Those three problems have different fixes, and most students study as if every miss were the first kind.
Content gaps get drilled skill by skill. Execution errors get fixed by changing a habit, like underlining what the question actually asks for or writing units next to numbers. Timing losses get fixed by raising your cutoff discipline, not by learning more math.
Also review the questions you got right but guessed on. Those are content gaps that happened to pay off, and they will not pay off next time.
Reading the score honestly
Bluebook gives you a score, but remember what it is. College Board does not publish raw to scaled conversion tables, so any number derived from a raw count, including the one our score calculator produces, is an estimate. Ours is accurate to roughly 40 points per section.
That means a 40 point move between two practice tests is noise. A 120 point move is signal. Track the direction over several tests rather than reacting to any single one.
The domain breakdown is more actionable than the total. Missing six Advanced Math questions matters more than missing three Geometry ones, because Advanced Math is about 35 percent of the Math section and Geometry and Trigonometry is about 15 percent.